It would depend on the degree. If he was sent back to get a B.Comm, BA in Econ. or MBA - absolutely fair. At the executive level, you're dealing with a lot more theory and are more detached from the day-to-day stuff, so that knowledge he gets in university could open up some avenues of thought he hadn't ever considered or known about before. his experience = good. Knowledge + experience = better. ;-)
If, however, he went and got a degree in, say, Fine Arts, then I'd say it's a bad business decision, as it wouldn't add near the value. The company just wants to see some letters after his name, in which case he could have sent money to Diploma Mill Inc. and saved himself years of headaches.